Red lake.



,UNETEI)? STATES PATENT osrion;

OTTO ERNST, ()F I-ICGHST-ON-THE-MAIN, GERMANY, ASSIGNOR fro FARB- WE um. V RM. Muis'rER, LUCIUS & BRUNING, OF HOoHsT-ON-THE- MAIN, GERMANY, A CORPORATION OF GERMANY.

RED LAKE.

Specification of Letters Patent:

Patented Sept. 4, 1906,

To all whom, it may concern: 4

Be .it known that l, OTTO ERNST; Ph D. chemist, a citizen ofthe Em ire of Germany, residing at llochst on-ther Iain, Germany, have invented certain new and useful Impro veinents in the Manufacture of Red Color. Lakes, of which the following. is a speoification.

I have found that the, dichloro'anilin sulionic acid obtained by nitrating monosulfonated orthodichloro-benzene and subsequently reducing or b sulfonating 3.4-dichloro-anilin yields w en diazotized- .and combined with 2.3.6-beta-naphtholdisulfonic' acid a dyestufl s ecially suitable for the manufacture of co or-lakes distinguished by their greet-fastncss to light and. purity of the yellow-red shade. I

Though the dyestufi contains three sulfa groups, the lakes are easily precipitated by tl1e difi'ercnt methods and of very great fastness to water. They are specially suitable for wall and variegated aperprinting,1ithography, and painters co ors.

Example: Two hundred and sixty-six parts, by weight, of dichloro-aniliii sulfonate of sodium are dissolved in the requisite quantity of water, to which is added a solution of sixty-nine arts, by weight, of sodium nitrite, and tile mixture is run into dilute hydrochloric acid containing somewhat more than two equivalents-that is, about eighty parts, by weight of hydrogen chlorid. The temperature of the solutions may be 15 centigrade. The diaizo-dichlormbenzene sul ionic acid thus formed is soluble with difficulty and separates for the greater part.

The diazo compound is run into a solution'of three hundred and sixty-five parts, by

- stufi se arat es dred and thirty rams of soda-ash. The dye-. for the greater part as an or-' ange-co ored precipitate. may be further completed bygtdding some common salt. When dry the dyestuif is a weight 2 ;3.6-beta naphtholdisulfonate of: sodium (R-salt) containing about one hun The precipitation brick-red owder, insoluble in absolute aloe-j hol, solub e in Water with a red-yellow color,

its a ueous solution being hardly changedby a ding mineral acids. adding some common salt the dyestuff is precipitated.

Having now described my invention, what I claim is a As a new product, the yellow-red monoazo dyestufl' obtained by the action of diazotize'd 3 :4-dichloro-anilin-fi-sulfonic acid on 2:3 :6- betf-naphtholdisulfonic acid having the'for mu a:

When dry; the dy'estufl is a brick-red furs der, insoluble in absolute alcoh0l,;solu b in water with a red: ellow color; its aqueo' sso OTTO ERNST.

Witnesses ALFRED Blnsnors, BERNHARD ln'nuonnn. 

